# How to count number of ones and zeros in a binary number?

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ASHA PON2022-11-29

I am having some set of binary numbers. I need to count the number of ones and zeros in each binary number. If a binary number has even number of ones then the output has to be '1' or it has to be '0'. Thank you in advance.
Example:
A=1100
B=0100
output of A =1
output of B = 0

### 采纳的回答

Davide Masiello 2022-11-29

I will assume that your binary numbers are stored as a character array, which is how Matlab normally works, e.g.
A = dec2bin(20)
A = '10100'
B = dec2bin(21)
B = '10101'
Now in the example above, A has an even and B has an odd number of ones respectively.
your desired output can be easily obtained with
1-mod(nnz(A=='1'),2)
ans = 1
1-mod(nnz(B=='1'),2)
ans = 0
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ASHA PON 2022-11-29
Thank you for the reply. This is what i needed.

### 更多回答（1 个）

Chunru 2022-11-29
% if you use char to represent binary numbers
A='1100';
mod(sum(A=='1'), 2) == 0
ans = logical
1
% if you use double to represent binaray numbers, you can do the conversion
% first
A = 1100;
A = num2str(A)
A = '1100'
mod(sum(A=='1'), 2) == 0
ans = logical
1
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ASHA PON 2022-11-29
Thank you for the reply. Actually i am having an array of 15 binary numbers and i need to apply the above mentioned concept to each numbers.
Example:
A=[ 1110, 0111, 0110, 1111]
Expected output:
B= 0, 0, 1, 1

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